1. Field of the Invention
The present invention relates generally to roll-on and roll-off trailers for transporting objects and, more specifically, to an improved tiltable trailer for transporting containers between locations such as between job sites and storage sites.
2. Description of the Prior Art
A great variety of trailers are known in the prior art for transporting "containers" in both residential and commercial type applications. Although the size of such containers varies with the industry, many businesses use large containers of the type similar to sea cargo containers. These containers typically have dimensions, on the order of, 10 feet high by 40 feet long with a weight on the order of 9,000 pounds or more. Such containers provide an economical method for moving items and can also be used for temporary storage. In the typical case, the storage container is transported to a site and is unloaded and left for a period of time during which period the container is loaded. Once loaded, the container is transported to a new location for unloading or storage.
Although such containers provide a convenient mechanism for moving and temporarily storing freight, household items, business inventory, refuse, and the like, handling of the containers presents a problem. In some cases, loading and unloading of such containers from the trailer is accomplished by a fork lift or other similar industrial lifting equipment.
Another solution to the problem of handling such large containers is the use of detachable container systems known as roll-on, roll-off arrangements. These systems typically feature a bed or frame which tilts to facilitate the loading or unloading operation.
One type of trailer for transporting removable containers in common use is the refuse trailer which is typically towed by a tractor rig and which is outfitted with hydraulic and/or electric systems for loading, unloading or otherwise handling the removable container. These type trailers are used for transporting empty refuse containers from a storage terminal to a job site where the container is typically left behind for the collection of refuse, solid waste or like material. The full container is eventually collected and taken to a dumping depot, or back to a storage terminal. The containers are typically of heavy steel construction and are made to carry heavy loads which vary greatly in nature, i.e., garbage, industrial or commercial wastes or by-products, etc.
The trailer used in refuse loading and unloading operations has typically been provided with an undercarriage carrying a tilt frame. The tilt frame is moveable between a level position for transport and an inclined position for loading and unloading from the rear of the trailer. In the inclined position, the tilt frame defines a single piece ramp which slopes at a uniform angle. A container, resting on the ground, is hoisted onto the ramp. The tilt frame is then lowered back to a level position for stably transporting the container over the road. To unload the container, the tilt frame is tilted to again allow the container to slide off. A chain drive or cable mechanism is usually present to control the movement of the container. U.S. Pat. No. 5,460,473, issued Oct. 24, 1995 and U.S. Pat. No. 5,324,160, issued Jun. 28, 1994, are typical of tilt bed trailers used for transporting containers of the above type.
While the tilt trailer systems of the type described have met the needs of particular job applications, certain drawbacks have continued to exist. These type tilt trailer systems have, in the past, been powered by specially constructed, single purpose trucks. Also, the prior art devices have often required specially designed and built containers, for example containers equipped with wheels and roller systems. Also, the tilting mechanisms of the prior art devices have often been complicated in nature, expensive to build and difficult to maintain. In some cases, the containers being handled were drug over the ground or surrounding substrate with consequent wear or damage to the container undersides.
In certain industries, the containers which are required to be transported are of such a size and weight as to be transportable by a trailer of simpler design which can be hauled by a general purpose truck. For example, some retail stores such as Walmart, K-Mart, and the like utilize storage containers containing retail goods which are of predictable, basically non-perishable nature with the containers being stored on the retail store premises, at least temporarily. At times, it is only necessary that the container being used for storage be moved from one location on the storage lot to another. On other occasions, it may be necessary to transport the container to or from a retail location over an interstate highway. It would be desirable to provide a trailer for transporting the containers used in such industries which was of simpler and less costly design than the typical refuse collection trailer system. Ideally, this special purpose trailer would be hauled by a standard, general purpose hauling vehicle, rather than by a special purpose vehicle or semi-rig. A standard truck would be less expensive and easier to maneuver in tighter spaces. It could also be detached from the trailer and used for other purposes.
Accordingly, the present invention has as its object to provide a trailer for transporting containers which uses a simple tilt mechanism which is economical to manufacture, yet which is durable in construction and easy to maintain.
Another object of the invention is to provide such a trailer for transporting containers with a novel tilt mechanism which utilizes a centrally articulated lift bed.
Another object of the invention is to provide a tilt frame trailer having a rear roller and chain drive arrangement which facilitates loading and unloading containers to be transported without damage to the container undersides.
Another object of the invention is to provide such a trailer which can be connected to a general purpose truck, such as the bed of a pickup truck by means of a ball affixed to the truck bed and a "gooseneck" type coupler arrangement provided as a part of the trailer.